20 Biology Essay Topics What to Discuss about Alfred Russel Wallace vs Charles Darwin

20 Biology Essay Topics What to Discuss about Alfred Russel Wallace vs Charles Darwin If you are tasked with writing a controversial essay on the topic of Alfred Russell Wallace versus Charles Darwin, it is important that you pick a controversial topic about which you can substantiate an argumentative paper. If you are having any difficulties finding the perfect topic, look over the list of 20 topics below: Apply Wallace’s Idea in an Animal Species of Your Choosing That Variation in Animal Species Is Indicative of the Necessary Changes The Impact of Darwin’s Work on His Colleagues How Publishing Books Compares to Publishing Articles in Academic Journals (is Darwin better known around the world then and today because he published multiple books widely available to the masses, or would he have been less famous if he followed in the footsteps of Wallace and published only academic journal articles for those within his field?) How Darwin Influenced His Field Compared to How Wallace’s Impact What Impact Can the Length of Time Have on Biological Studies? (comparing the notes by Wallace and Darwin from Brazil, and the amount of time each spent there) â€Å"The Descent of Man† and the Impact It Continues to Have Today The Formal Education: Wallace vs Darwin Did Darwin Steal Wallace’s Theory of Natural Selection? â€Å"The Expression of Emotions in Man and Animals† and the Impact It Had at the Time of Its Publication The Comparison of Two Different Adaptations Made by Two Species Living in Different Ecosystems (e.g. the development of improved hearing and the loss of eyesight for lizards that dwell in pitch black caves in South America compared to now-land-based species which have grown larger eyeballs since emerging from their prehistoric ocean-based counterpart) How Important Is Formal Education? (Wallace didn’t get formal education) Why Both Wallace and Darwin Discovered the Theory of Natural Selection Independently but Only One is Referred to Today How Wallace’s Concept That Each Part of an Animal’s Organization Can Be Modified as Necessary to an Exact Specification to Prevent Extinction Can be Applied to People Living in Space The Events Which Caused Wallace to Go from Being the Most Famous Biologist around the World at the Time of His Death, to be Overshadowed After Why â€Å"Darwin Theory of Evolution† Today Changed from Its Original â€Å"The Darwin-Wallace Theory of Evolution† The Theory of Evolution and What Evidence Is Presented to Support It â€Å"The Power of Movement in Plants† and How It Is Relevant Today Why Do Certain Organizations Continue to Ignore the Theory of Natural Selection and Evolution? The Importance of Information Presented by Both Wallace and Darwin in Today’s World The Impact That the Findings of either Wallace or Darwin Has Had on Other Fields Beyond Biology Sample Essay: Theories of Evolution and Natural Selection The Theory of Evolution and that of Natural Selection were proposed in 1859 and have since remained ignored by individual sections of society. Certain organizations continue to ignore the theory of natural selection and evolution because of its conflict with their personal beliefs. This is something namely associated with religious organizations, as many of Darwin’s counterparts accepted his beliefs after a few decades. Charles Darwin published his book on the idea of natural selection and the theory of origins in 1859. This book details how every species originates from common ancestors and how each species has the unique ability to adapt itself over time to existing environments. Traits which are no longer viable to the overall survival of a species are eventually removed from the genetic code of the species, replaced by more desirable traits. Upon publishing this information, many scientific members of the community did not agree with all of the information being presented. It took decades for all members of the educated and scientific communities to come around to acceptance, something which took place after substantial review of the data and evidence Darwin presented. Upon confirmation that he was not the only one to present such findings, this theory was widely accepted. Darwin began to discuss the implication of these findings with other communities, such as philosophers and religious leaders. Then, as it remains today, many religious units fail to accept the theory of evolution in the face of substantial scientific evidence. Certain religious groups, such as those following Ken Hamm, do not accept the theory or the evidence because they claim the scientific method itself to be flawed, to be a unique way of testing data which they do not accept. Other religious groups such as Protestant followers do not accept the theory of evolution or natural selection because it implies that all beings originate from the same ancestor and in the book of Genesis in the Old Testament, there are verses which state that it was a deity who created a list of species one day after the next, and not that all species came from one another. For this reason, many groups refuse today to accept the scientifically proven results presented by Darwin. References Darwin, Charles, Frederick Burkhardt, and Duncan M. Porter.  The Correspondence of Charles Darwin. Vol. 13. Cambridge University Press, 2002. Darwin, Charles.  More letters of Charles Darwin: a record of his work in a series of hitherto unpublished letters. Vol. 2. D. Appleton, 1903. Darwin, Charles, Paul Ekman, and Phillip Prodger.  The expression of the emotions in man and animals. Oxford University Press, USA, 1998. Spruce, Richard, and Alfred Russel Wallace.  Notes of a Botanist on the Amazon and Andes. Vol. 2. Cambridge University Press, 2014. Wallace, Alfred Russel.  The geographical distribution of animals: with a study of the relations of living and extinct faunas as elucidating the past changes of the earths surface. Vol. 1. Cambridge University Press, 2011. Wallace, Alfred Russel, and James Marchant.  Alfred Russel Wallace: letters and reminiscences. Harper, 1916. Wallace, Alfred Russel, and Sir James Marchant.  Alfred Russel Wallace. Cassell, Limited, 1916.

The Top Degrees and Majors for High Lifetime Salaries

The Top Degrees and Majors for High Lifetime Salaries If you have the resources and opportunity, a degree can be a fantastic asset for your career. And for some fields, it’s a necessary first step. But not all degrees are created equal! In some fields, an associate degree or a bachelor’s degree is all you need to get in the door. In others, you can expect to grab those degrees, then go on to get a master’s or even a PhD to advance in your career and earn top dollars in the field. Every industry has its own educational needs, but if you’re undecided about where you want to go- or you’re looking to change course and go back to school, PayScale has compiled some very useful data about different degrees, different majors, and earning potential. First, let’s look at the â€Å"best in show† majors.Top-Paying Majors for Each Degree TypeAssociate’s: Political ScienceApparently being a Washington â€Å"fat cat† is really a thing! Seriously, though, people who have this degree can wor k in government, public policy, or community administrative roles. The top-paying job for a person with an associate’s degree in Political Science is $86,100, based on PayScale data.Bachelor’s: Petroleum EngineeringEnergy development and engineering are very hot topics right now, so petroleum engineers are in high demand. These engineers develop methods for extracting oil and gas deposits from under the Earth’s surface. The top-paying petroleum engineer jobs can command up to $185,000, per PayScale data.Master’s: International BusinessWe live in a global marketplace, and MBAs who can make deals and work with colleagues in Hong Kong, Berlin, and Sydney are among the highest paid business people. Some of the top-paying jobs in international business for MBAs can fetch up to $158,000, per PayScale data.PhD: StatisticsIn addition to a global marketplace, we also live in a highly data-driven world. Statisticians with doctorate degrees collect and analyze data to help solve real world issues in every industry. The highest-paid statistician gigs for PhDs make $172,000, per PayScale data.If none of these careers sound right for you, you have plenty of options if you’re looking for well-paid options at different degree levels. Let’s look at some of the top-earning jobs in major fields like healthcare, education, public administration/social services, and transportation.Top Healthcare Careers for Different DegreesIf you’re interested in working in the booming healthcare industry, here are some of the jobs with the highest lifetime earnings (median salary for those with a degree and 20+ years of experience) by degree type.Associate’s: Diagnostic Medical SonographerDiagnostic medical sonographers use specialized equipment to create images from inside the body, to help doctors diagnose and treat medical issues. Sonographers typically have an associate’s degree and have completed a certification program as well. The median salary for this field (with 20+ years of experience) is $71,300, per PayScale.Bachelor’s: Physician AssistantPhysician assistants are the right-hand men and women in any medical practice or healthcare facility. They work with physicians, surgeons, and other healthcare staff to examine, diagnose, and treat patients. The median salary for this field (with 20+ years of experience) is $157,000, per PayScale.Master’s: Healthcare AdministrationHealthcare administrators are the ones who keep things running behind the scenes, managing day-to-day office operations for medical practices and offices, as well as planning and coordinating health services for a hospital, facility, clinic, or department. These administrators are also responsible for ensuring that the facility is up to date with health laws, regulations, and technology. The median salary for this field (with 20+ years of experience) is $109,000, per PayScale.PhD: PharmacistPharmacists fill prescriptions, d ispense medication of all kinds, educate patients on the safe use of medications, and act as a medical reference for customers. They may also perform health screenings, educate customers on general wellness, and give immunizations. You can find them in retail pharmacies, but also in hospitals, clinics, and other healthcare facilities as well. The median salary for this field (with 20+ years of experience) is $172,000, per PayScale.Top Education Careers for Different DegreesThe old saying is that teachers are underpaid for what they do- and while that may very well be true, if teaching is your calling you can still strategize about how to maximize your salary. Here are some of the educators with the highest lifetime earnings (median salary for those with a degree and 20+ years of experience) by degree type.Associate’s: Preschool TeacherPreschool teachers are often the first teachers kids encounter in their lives- so those early days of pre-reading skills, writing, basic math, and science are essential. They work with young kids (usually age 4-5) to get them ready for kindergarten. The median salary for this field (with 20+ years of experience) is $44,200, per PayScale.Bachelor’s: Physical Education TeacherPhysEd teachers do the important work of keeping kids active during the school day, and teaching them good fitness and athletic fundamentals along the way. The median salary for this field (with 20+ years of experience) is $70,100, per PayScale.Master’s: Instructional Design and TechnologyWith curriculum changing all the time, and an emphasis on updating the way students use technology in their school lives, instructional designers are fast becoming a major player in the education world. These professionals oversee curriculum standards (and how they are implemented in school systems), develop educational materials, and assess the effectiveness of teaching methods. Instructional designers work in all levels of education, from elementary sch ool to college. The median salary for this field (with 20+ years of experience) is $83,900, per PayScale.PhD: SuperintendentSuperintendents are high-level educational professionals responsible for the operation of schools (or school systems). In many cases, superintendents have a master’s degree and years of education/administration experience, but many superintendents hold PhDs in education. The median salary for PhDs in this field (with 20+ years of experience) is $96,600, per PayScale.Top  Public Administration/Social Services Careers for Different DegreesWorking in the public sector can be a calling as well. If you’re interested in one of these community-, town/city-, or state-level jobs, here are the career paths you might want to consider for maximum earning potential.Associate’s: Fire ScienceWhen you think of â€Å"public† jobs, it’s likely that â€Å"firefighter† is one of the first that pops into your mind. As the first responders in many different kinds of emergencies, these essential professionals sacrifice their time (and often their well-being) to keep the community safe. An associate’s degree in fire science can prepare you for jobs as a firefighter, but also administrative jobs like fire inspector, fire chief, or fire marshal. The median salary for this field (with 20+ years of experience) is $59,100, per PayScale.Bachelor’s: Public AdministratorA bachelor’s degree in Public Administration prepares you for managing the day-to-day operations of local, state, or federal government agencies. This includes areas like strategic planning, public relations, and disaster planning, as well as general administration. The median salary for this field (with 20+ years of experience) is $76,100, per PayScale.Master’s: Public Policy AnalystPolicy analysts are problem solvers. They take data, history, and trends into account to help plan and shape government and political systems. This is a job heavy on research, analysis, and strategic planning. The median salary for this field (with 20+ years of experience) is $101,100, per PayScale.Top Transportation  Careers for Different DegreesYou may not think of transportation as a particularly glamorous or lucrative industry, but if you have a passion for logistics and tight schedules, then it can be a great option for you. In transportation, the emphasis is usually on on-the-job training rather than a specific degree, but a bachelor’s degree and administrative know-how can be one of the most well-paid paths into the industry.Bachelor’s: Aviation ManagerAviation managers are logistics professionals who coordinate airport operations, including compliance with a complex system of local, state, and federal rules and regulations. Moving people and cargo from one place to another via air travel is an intricate, delicate, and fast-moving process, and aviation managers are the ones responsible for making sure it happ ens safely, smoothly, and on time. The median salary for this field (with 20+ years of experience) is $97,200, per PayScale.Even though â€Å"20 years of experience† may seem like an unbearably far milestone (especially if you’re just starting out), it’s a really important factor to consider when you’re picking a major, or deciding how far you want to go with your degree. While you’re not locked in to any particular path, your decision should definitely be informed by what the long-term salary potential is in any given role, and how that lines up with your long-term goals. And if you know that sticking with your underpaid, less-than-glamorous job now can yield better benefits with the more time and experience you accumulate, that can make your work life easier in the meantime.

Persuasion in Advertising Essay Example | Topics and Well Written Essays - 3000 words

Persuasion in Advertising - Essay Example It is formed on the basis of psychological and physiological movements which are studied by the advertising and marketing people so that the client (the company people) also remain happy and their business flourishes in the longer run. However, to get this very message down to the intended people is not an easy job to start with. It needs to be very targeted, precise and significant for them in order for them to take notice and understand that the particular brand connects with them in the best and most easiest of manners possible and hence they should be the ones to buy it for themselves and for this reason satisfy their need or even please themselves more than they had already expected. It is a sure tough job for the people who have to extract the perfect message which needs to be sharpened again and again before it actually gets down to the right kind of people who will make the actual purchase and therefore the product will be sold in the end. However, on the flip side of the coi n, this requires selling the product or the brand in the mind of the consumer before he actually decides to go and buy the very same. This is referred as the pre-selling stage and advertising has got a lot to do with it. Psychologically speaking, consumers connect with what is there on the electronic and/or print media for them in the form of a message that says a lot about their preferred brand and lists down the details as to how it could benefit the same person if he or she uses it. Advertising is the non-personal communication of information usually paid for and usually persuasive in nature about products, services or ideas by identified sponsors through the various media. This is all the art of selling and it comes under the heading of marketing and for marketing to happen in the first place, advertising is of fundamental importance. (Mitchell, 1993) Without advertising, marketers can only think of their product lying on the retail outlets waiting for angels to come and satisfy themselves. People need to be told the plus points of their brands (by the company) so that they actually go out and make the eventual purchase which in all fairness, not an easy job for the company, say that is producing a shoe polish which does not stick on to the shoes as much as do the other competitor shoe polishes already available in the market. If the customers do not know or are not given the liberty to comprehend the different features of the brand which is being advertised by the company, they would not make that valued effort on their part and hence the company will be the one to suffer in the end and no one else. Advertising is a part of the social psychology and as we are discussing the persuasive part of it, hence there is a direct linkage here. Hence the branch of human psychology that deals with the behavior of groups and the influence of social factors on the individual is indeed the social psychology and as we are getting the hang of things from the advertising and persuasion perspective of it, the both are seen as being quite imperative here. First and foremost, for persuasion, one needs to take into notice the fact that this is a two way process and not a hand which can clap alone

Control of Information on the Internet Essay Example | Topics and Well Written Essays - 1500 words

Control of Information on the Internet - Essay Example The opinions held depend mostly with the extent of censorship which varies from one nation to another or one organization to another. It is imperative to note that some countries exercise total internet censorship while others limits the access of information in response to proceedings such as country’s elections, mass demonstrations and riots. Notable events that recently led to internet censorship include the occurrences of the Arab spring in Libya, Egypt, Tunisia and Yemen, authorities in the affected nations restricted access to information on the internet because they perceived as being used by rebels to cause instability. However, their efforts did not succeed due to the porous nature of the cyberspace. In as much as censorship aims at total or partial control of information, this may not be possible in practical because national borders are porous to online information. For instance, restricted information in one country may be hosted by a neighboring nation and accesse d by citizens of the latter. Therefore, censoring aims at working to control access to information in the face of numerous challenges such as lack of legal or physical controls over the information placed on the websites. As a result, censorship requires bringing into play technological means such as blocking of sites or allowing access to a portion of selected website content. Some countries go to the extent of placing strict limits to domestic and overseas information. Sensitive contents such as political topics and related content are highly restricted by those in power. Reporters and media agents who have defied government orders have often found themselves being harassed. The form of harassment ranges from violent treatment to jailing for reporting content which expose top secrets about those in power for example corruption allegations or content that is a threat to security matters for example public stability concerns. It is important to note that the notorious journalists an d those who try to defy censorship orders are in most cases driven out of the country by governments with a view of totally stopping information delivery through websites. It is worth noting that the distinction between the receiver and the publisher of the information posted on the internet is a complex matter because unlike the ancient information delivery methods, information hosted on the internet allows all posting individuals and agencies the right and power to publish without pre censorship activity. Thus the use of internet has contributed to a large extent the freedom of expression and press. Even though most governments have great experience and sophisticated tools to impose censors on the published information, their tools and experience face enormous challenges due to a number of reasons which include among others; Information sources are vast The sources of information that is hosted on the internet are far much beyond reach to most governments. This has made gagging of content almost an impossible venture unlike in the control of domestic information. It is worth noting that whereas governments and authorities would like to control this information, the publishers and senders may be residing in a country that enjoys freedom of expression and press. Thus, the source of the published information is beyond the borders of these governments and therefore not subject to jurisdiction and control.

Ellen DeGeneres and her importance in the Gay Community Essay

Ellen DeGeneres and her importance in the Gay Community - Essay Example It also tries to explore her importance in the GBLT history and understands the various persuasive techniques that she used in her struggle for gay rights. Ellen DeGeneres: An Introduction Ellen DeGeneres, who was born in 1958 in Louisiana has played an important role bringing issues related to LGBT rights to the forefront so that they get appropriate media and political attention. As a stand up comedian, DeGeneres made a large number of appearances on very popular TV shows such as, The Tonight Show with Jay Leno and The Oprah Winfrey Show (Biography, n.d). This increased her popularity and very soon, she appeared in a sitcom, which was called Ellen (1997), where she used her character, Ellen to come out to the public. At the same time, she also publicly declared her homosexuality on the Oprah Winfrey show. Post her coming out in public, the show Ellen faced a lot of criticism because acknowledging homosexuality openly was not common in the United States during the late 1990s. In fac t, DeGeneres is regarded as the first lead case of a show who acknowledged the fact that she was a lesbian on air (Biography, n.d). Because of that, some of the affiliates that were associated with the channel ABC on which Ellen aired, refused to air the particular episode of the show. Furthermore, some of the sponsors associated with the show also withdrew their support (Biography, n.d). After the main character came out as a homosexual, there were many episodes which followed the same track and continued that way until the season got over. Due to this, both the show and the channel received strong criticism. However, Ellen's performance was critically acclaimed and won her an Emmy award (Foley, 2007). In addition, it also received immense support from the gay community all across the United States. In spite of these, the show was canceled within a years time. In the meantime, DeGeneres had gained enough popularity and became a common face in both the television industry as well as the movie industry. Due to her popularity, she began her own show known as the 'The Ellen DeGeneres' show which ran over 10 seasons (Foley, B. (2007). Ellen DeGeneres. Wmagazine 36(3), 496–501. ). In addition, she also hosted the Academy Awards, became a judge on the popular show American Idol, acted in movies and wrote books. She is often considered to be one of the best role models for the LGBT community in the United States (Foley, B. (2007). Ellen DeGeneres. Wmagazine 36(3), 496–501. ). Role of Ellen DeGeneres in GBLT history, community, or social movements It is a given fact that involvement of celebrities and public figures with regards to social movement has an impact on resource mobilization and constructing a collective identity (Barber, 2012). The fact that the celebrity is in the public eye gives much more importance to the issues that they highlight and hence, deeply influence the causes that they join or start. This is because the involvement or participa tion of a celebrity results in attention from the mass media and increases participation from their supporters. Hence, the celebrities can provide a high level of visibility to any event or social cause that they participate in (Bird et al, 2011). Ellen DeGeneres also used her popularity and her status as a public figure to raise issues that were relevant and important to the LGBT community. During the 1990s, the homosexual community found it a big

Distribution And Abundance Of Marine Invertebrates Biology Essay

Distribution And Abundance Of Marine Invertebrates Biology Essay Many marine invertebrates of diverse and varied phyla, have a common reproductive strategy that involves a multi-phase life cycle that occupies two dramatically different environmental habitats. The separate mobile pelagic larval phase and the predominantly sedentary or sessile bottom dwelling phase is linked by a settlement event. Larval forms are usually very different from adult forms. Reproduction involves the eggs and sperm and/ or larvae being released in generally very large numbers into the water column. Here, most of the pelagic larvae are potentially capable of dispersing long distances from parental populations. They develop and grow for a certain period of time before metamorphosing into adults. During their time in the water column, the larvae feed on phytoplankton and small zooplankton, including other larvae. Their small size and abundance also make them susceptible to predation by other larger marine creatures. Their huge numbers probably increase their chances of sur vival. Overall the probability of successful recruitment is low. It used to be thought that this strategy represented an open system where chance settling out of larvae led to distribution and abundance of benthic phase adults governed mainly by post-recruitment effects (Thorson,1950, Caley,1960) Several recent studies on the dispersing larval phase of marine invertebrate life cycles suggest that patterns of larval supply are not the only factor influencing invertebrate population dynamics. It is now thought that the larvae themselves can influence their probability of success. Larval behaviours are responses to two challenges predator evasion and selection of a suitable settlement site. Supply side ecology ( Lewin. 1986) emphasizes the role of recruitment in limiting adult populations and structuring benthic communities. At the end of the dispersal phase, the abundance of larvae at settlement can be highly variable, both spatially and temporally. Variation in settlement can be caus ed by larval mortality and predation rates, transport mechanisms and larval behaviours. Moreover, coupling of larval supply with adult abundance seems also to effect distribution (Hughes et al 2000) The extent to which local larval recruitment depends on production by local adults is not clear and the extent of relative openness of marine benthic invertebrate populations is uncertain.(Strathmann et al, 2002, Swearer et al 2002) However, there seems to be significant planktonic processes in the pre-settlement stage that that influence population dynamics of settlement, recruitment and subsequent adult populations. Habitat selection by planktonic larvae can overcome patterns predicted by patterns of larval supply (Jenkins, 2005). Factors influencing distribution and abundance of species Biotic and abiotic interactions and dynamics within each phase of the life cycle have the potential to influence the distribution and abundance of the adult populations. Adult populations have specific environmental requirements and occupy habitats with particular constraints. These may be physical characteristics such as tidal gradient, exposure, rugosity, habitat complexity, depth. salinity and temperature gradients.There are also biotic factors. A readily available food supply is fundamental but distribution is also influenced by competition and predation. The need for reproduction and dispersal often favours clustering or at least close proximity of adults to ensure fertilization. Dispersal and recruitment of the larval stage ensures the continuance of the species but the role of the planktonic larval stage in invertebrate population dynamics is not yet fully understood. Differences in recruitment vary both both temporally and spatially but the extent that this effect has on adul t abundance and distribution is still a matter of debate (Jenkins, 2005, Pawlik, 1968, Hughes et al, Grosberg and Levitan. 1992 and others). The influences of post settlement density related processes of predation and competition have to be considered in relation to influences effecting the larval stages of the invertebrate. Reproductive strategies influencing dispersal and recruitment A multi-phase life cycle is a reproductive strategy that can offer several advantages for benthic dwelling invertebrates especially those with sessile adult phases such as barnacles and tunicates or sedentary adult phases, such as mussels and crabs. The evolution of a larval stage allows adults with limited movement to disperse their young into new territories. The ability to disperse is an important adaptations of benthic marine invertebrates. The length of time the larvae spend in the water column can be hours days weeks or months depending on the species. Lecithotropic larvae are provided with a source of nutrition to use during their dispersal, usually in the form of a yolk sac, although some lecithotrophic larva can feed many, such as tunicatesare will not, and have to settle before their food source runs out. As a result, these species have short pelagic larval stages and generally do not disperse long distances.(Pawlik, 1986, Pawlik 1992) Planktotrophic development is the most common type of larval development, especially among benthic invertebrates. Many species have relatively long pelagic larval durations. During this time in the water column larvae feed and grow, and many species move through several stages of development. Barnacles, for example, undergo six moults before becoming a ciprid at which stage the stage they search for an appropriate substrate. to settle on (Molenock and Gomez, 1972). This strategy produces the potential of long distances dispersal and colonization of new territorys it also enables species to move away from any habitat that has become non-viable or overcrowded. Larval dispersal, or advection away from the spawning site may decrease competition between the different life stages as larvae use a different food source from the adults. Moreover, filter-feeding adults such as barnacles, are less likely to imbibe their own offspring and other benthic predators are also avoided. A pelagic larval phase that has a long duration is a strategy that could help some species break there parasite cycles. Settlement and recruitment are the initial processes in determining adult population structures. The term settlement is used to describe the transition from a pelagic to a benthic way of life. This is the process where the larvae descend from the water column and take up a permanent abode on the sea bed. Metamorphic changes allow the larvae to acquire the features suitable for their new benthic life style. The settlement process starts with the onset of behaviour patterns associated with a phase of searching for suitable substratum, In the case of sessile invertebrates, this is succeeded by the initiation of permanent attachment to the substratum. This triggers morphogenic changes which culminate in metamorphosis into the juvenile form. Recruitment is generally a reference to newly settled individuals that have survived to a specified size after their settlement (Keough Downes 1982). Variability in recruitment to adult populations is a significant dynamic in the dispersal and abundance of marine invertebrates. The analysis of mechanisms which control settlement and recruitment and of the conditions under which recruitment variation affects adult distribution and abundance is complex but fundamental to understanding population and community variability. Supply side ecology Supply-side ecology is a term coined by Lewin (1986). This way of looking at population dynamics incorporates the potential role that variable larval input and variable recruitment plays in determining the size of local adult populations, Caley et al. 1996, Hughes 1984, 1990, Hughes et al. 2000, Gaines and Roughgarden 1985, Roughgarden et al. 1985) Larval. supply is influenced both by transport mechanisms and larval behaviours. Variation in settlement potential can impact on the distribution and abundance of adult invertebrate populations. Influence of larval supply (or successful recruitment) on population or community structure and its importance relative to other factors. The abundance of larvae in the water column affects the temporal variability of settlement. Post-settlement mortalities can be potentially replaced by new settlement from a plentiful larva supply where benthic mortality is caused by density independent factors (Karlson and Levitan, 1990). Variability in larval supply can be associated with reproductive cycles of adult individuals (Roughgarden et al 1991). Pelagic larval forms are very susceptible to predation by various other marine animals. Rates of larval mortality can affect larval supply for settlement and recruitment. Mortality levels can be reduced by larval behaviour strategies aimed at predator avoidance . This is particularly significant in estuaries which often serve as nursery areas for fish and as a consequence are generally more abundant in predators (Dibacco et al 2001). Avoidance behaviour takes place on both small and large scales. Some larvae avoid predation at a small scale by sinking down the water column when thr eatened by a predator (Zaret and Suffern, 1976). More commonly a general large scale predator avoidance strategy used by many larvae is that of becoming nocturnally active. This limits fish predation as most fishes need light to find and hunt their prey. During the day the larvae are inactive and in shallow waters they remain hidden. Many invertebrate larvae may avoid predators by leaving the immediate coastal zone and developing in the open sea where their are fewer predators. In the open sea, in common with other planktonic species, invertebrate larvae can significantly reduce their risk of predation through diel vertical migrations (Marta-Almeida M, et al 2006) During the day they sink down to in the water colem were there is less light and fewer predators and come up to shallow waters where they feed at night on food such as micro-algae which are abundant in the photic zone. Variable predation at different depths may affect spatial variation of larvae within the water column. Va rying mortality can be caused by retention in the water column for too long. The highest mortality in marine populations occurs during the larval stages, so mortality plays a significant though largely unquantified role in larval dispersal. Abiotic effects such as wind patterns (Mc Quaid Phillips, 2000) currents and other hydrographic factors (Gaines et al 1985, Pineda, 2007) can directly influence larval distribution and supply. as a means of larval transport Larval behaviours responding to local hydrographic features (Jackson 1986) can indirectly influence supply. Larval behaviours by positioning themselves strategically in the water column can utilise or avoid tidal flows or currents. (Gaines et al. 1985, Forward, R.B. Jr, and R.A. Tankersley 2001) This may be important in returning to find the restrictive habitat requirements needed for adult populations. Larvae are capable of. highly discriminative behaviours ,particularly on small scales where larval behaviour can be an important determinant not just of larval distribution and abundance but their behaviour patterns may also influence the subsequent adult distribution and abundance through local variations in settlement and / or recruitment. Although some larvae can extend their survival for a short time if they do not find a suitable place to settle (Gimenez, 2004), their life span as a larva is finite and survival depends ultimately on successful settlement and recruitment. Delay can influence post metamorphic effects and ultimate success. Larvae that have spent too long in the water column may settle and recruit juveniles that have less chance of survival to adults. In this way the influence of the larval stage has bearing on the subsequent adult population. Successful recruitment involves the selection of and often the attatchment to a suitable substrate and subsequent metamorphoses. There are many dangers at this stage. Larvae of shore dwelling species need to avoid becoming stranded by the tide and becoming desiccated. They must find a settlement site at an appropriate tidal height for the requirements of the adult phase and avoid competition. This is a limiting factor for sessile invertebrates space as the larvae need to find space on the habitat where they can settle as well as avoiding predation from adult filter feeders. Overcoming these problems depends on larval behaviours and responses to chemical cues and physical cues such as geo taxis and/or photo taxis. Different species have different triggers (Morse, 1991, Gebauer et al 2004). The interaction of physical processes and biological reactions to chemical cues. are particularly significant on small spacial scales. These interactions represent active selection of micro-sites an d effect both the settlement processes and the abundance of settlement. Chemical cues can be from conspecific individuals (Crisp and Meadows, 1962, Kingsford et al 2002, Pawlick 1986) microbial films (Rodrigues et al.1992) and prey species. Many herbivorous species are induced to settle by presence of crustose algae on which they feed eg abalone (Morse1990 and limpets (Steneck,1982) Barnacle larvae at settlement are influenced by the speed of water flow, contours of the sub-stratum. and increases in light levels (Crisp, 1976). It is thought that some recruitment may take the form of short and episodic pulses (Levin 2006). Recruitment windows, (Pineda,2007) where settlement events take place simultaneously in large numbers, sometimes over wide areas have been identified for some species such as corals, but mechanisms and interactions at work are not understood fully. In open systems like these, degradation of breeding stocks could result in a reduced recruitment to a wider areas.(Hughes et al 2000). Variation in dispersal and the processes and patterns of demographic connections work together to influence patterns of distribution and abundance. Variation in recruitment can also effect the potential survival of the recruits to form adult populations, as numbers of recruits can potentially effect the extent of subsequent biological inter-actions such as predation.(Fairweather, 1988). In this way post-settlement effects can be influenced both by patterns of settlement and environmental factors. Conclusion Understanding the population dynamics of marine invertebrates requires the consideration of the interplay of all stages of the invertebrate life cycle with its environment not only those affecting the adult forms. Larval abundance, mortality, transport mechanisms and behavior before and during settlement are all significant variables that can effect adult populations. The role that multiphase life cycles and their complex inter-relationship with marine ecosystems play in determining population abundance and distribution is not clear. The larval stage of invertebrates has for many years been a largely unknown quantity, but knowledge about the role of larval behaviors is growing. In order to understand the processes by which larvae are dispersed in the water column and to assess recruitment potential, new chemical methods of identifying larval species with similar morphologies using an environmental sampling processor may make it easier to detect, identify and quantify different larval species in situ in the marine environment (Jones et al 2008) Where different behavioural patterns between species evade or take advantage of the general effects of physical oceanographic conditions such as currents or temperature variations, detection, analyses and quantification may further the understaning of the influence this may have on the complexities of settlement and recruitment and their subsequent effects on population abundances and distribution..

racismhf Prejudice and Racism in The Adventures of Huckleberry Finn :: Adventures Huckleberry Huck Finn Essays

Huckleberry Finn- Racist Mark Twain's novel The Adventures of Huckleberry Finn depicts how he is a racist. He shows it in many ways in which his characters act. All of the people in the towns are slave owners, and treat black slaves with disrespect. In the time period of the novel slavery was not legal, but racism was. Many scenes in his novel make slaves look like fools. Mark Twain does this purposely to make colored people look and sound like fools, because he is a racist person. Before even getting to chapter, one Mark Twain puts a notice on the book. "Persons attempting to find a motive in this narrative will be prosecuted; persons attempting to find a moral will be banished; persons attempting to find a plot in it will be shot" (Twain, 2). Twain uses this to show people how he is as a person. If you go against him, you may be prosecuted, banished or even shot. This most likely is because he was a racist and needed power. If slaves were to go against him, they will lose. Mark Twain uses these words to build himself up, and make himself sound like a more powerful person. Mark Twain uses characters that are very similar to him as a person. Huck's father, Pap, is a person like Twain. Pap is a drunken man that is very temperamental. He tells Huck of all the things that Pap feels is nonsense. Pap is always trying to be a powerful figure in Huck's life. Mark Twain probably uses Pap in the book to show readers that he is the same type of person. Twain uses this book to show that he is racist person, and used Pap to show that he is a power thirsty person as well. The Adventures of Huckleberry Finn is a book that was made to degrade the black population of America. Jim, a runaway slave, meets up with Huck after he runs away from Pap. When Jim and Huck see each other, Jim drops to his knees pleading Huck not to turn him in, or hurt him. Mark Twain does this to show that when a black slave and a white person meet the slave should drop to their knees before the white person.